[Refactor] Decouple the wallet class

[panleone]

Abstract

The file wallet.js is a real mess: There is no actual wallet manager class and it mixes GUI, crypto functions, ledger stuff and masterKeys. This PR begins a process of refactoring the class:

• A Wallet class has been added that at the moment incorporates all the ugly global wallet related functions that were in wallet.js. In the future Wallet will manage UTXOs, balance, addresses, masternodes...
• MasterKey class and derivatives have been moved to a new file masterkey.js, masterkeys should have the ONLY role of managing internally the generation of new addresses.
• Hence the global variable masterKey has been removed in favor of a global variable of type Wallet that has masterKey as a private field. At the moment I added a getter to masterKey (or the refactor would have been to big), in future PRs we should try to avoid exposing masterkey outside the wallet.
• Ledger related functions and variables have been moved to a new file ledger.js
• Finally a new file encoding.js has been created. It contains the low-level cryptographic functions that were previously in the wallet file.

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Testing

Test that the wallet functionality are still working as expected for example:

• Create wallet
• Import wallet
• Hit 'Refresh Address' in the Dashboard
• Encrypt (+ Change Password)
• Test Send + Receive
• Test Contacts (Add them, Send to them, etc)

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Note

As I already said the refactor is not final and I did not want to change too much lines. In future PRs the getter to masterKey and the function getDerivationPath should both be removed from the Wallet class. We should also really try to decouple the logic from the GUI

[JSKitty]

Before I add the "Awaiting Review" label to this PR, the 'Testing' section is going to need to be more detailed (the Quality Control team need to understand what to test, too vague and we might not get enough tests by folks).

[JSKitty]

Code-wise this is looking very clean and is a massive organisation to what we had before, I like it! 👍 🚀

I have some minor nits related to the MasterKey and Wallet classes, but many of them are out of scope to the PR (decoupling refactor) so I'll probably work on them in a different PR to keep this small and quick.

To real nits: I'm not sure cypher.js quite fits what we're using it for, maybe encoding.js would fit better? It is more En/Decoding than cyphering.

I'll get testing in the meantime. 🔧

[panleone]

To real nits: I'm not sure cypher.js quite fits what we're using it for, maybe encoding.js would fit better? It is more En/Decoding than cyphering.

totally agree

[Duddino]

tACK, tested wallet creation, sent to addresses + contacts and everything works

[Duddino]

Other than the leftover comment, tACK

[JSKitty]

tACK e6ddb9e

We also received positive tests from 4 Quality Control members.

[Liquid369]

tACK e6ddb9e
Ledger is also working again LGTM

[Duddino]

tACK ledger works fine